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Brake Piston Boots

Joined
8 August 2003
Messages
677
Location
West Sussex, England.
If you have a compressed air line, there is an easy way of getting the pistons through the boots and ready to push down the bore: locate both seals, place both pistons roughly on top of seals and pack the other side (top of piston to inside face of caliper) with timber packer, then blow compressed air through the bleed hole. Both seals will pop around the pistons perfectly, like magic.
 
Agree with NSXGB, that method makes it easy to put the pistons back in assuming you have air available. A rubber nozzle tip helps too.

I'm not sure what's up with the Centric kits, everything else from the kits I received fits fine except for the boots. I ordered another front seal kit recently that I think also had the wrong size boots but I'd have to double check. Is Rockauto giving me the wrong P/N or just some kits still on the shelf were messed up in packaging? Maybe they'll fix the problem soon enough and then I won't have to pay 10x for the OEM kits.

Anyways, I like the color of the silver calipers. Hopefully you're getting low-dust pads :)
 
I ordered the centric fronts and the rear boots too they did not work for me. Your front boots looks like the same ones I got a month or two ago. I put the rear boots in the ring land and insert the piston in. It all looked good, but when I push the piston out the boot would come out of the ring land. I'm thinking if your pads are 100% it would be fine but when they get low it might happen. I ordered some OEM
 
Hi, @Honcho.
In order to keep your thread clean, thought about sending this through PM but as others experienced similar issue, please allow me posting here.

First of all, have never installed the caliper service kit especially the dust boot from Centric and I don't even know whether it has the same design as the OEM one or not.
Only used the OEM one in my life (but done 100s of them) so could be completely wrong but from your photo, it looked as if the dust boot is not seated properly inside the caliper bore.



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Please allow me using and editing your original photo.
Yours is on the left side.

The largest diameter section of the dust boot (marked yellow) should sit within the bore opening, like on the right side.
With the similar piston position, you have fair amount of gap (marked red).




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You may want popping out at least one of the piston to double check the boot seating.

The base lip should be inserted and sit inside the narrow recess of the bore (marked green).

Hope I'm wrong.

Kaz
 
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Yeah it definitely looks like those dust boots aren't seated in the caliper. Centric kits should fit like OEM, at least they have in the Honda applications that I've used them in. The compressed air trick works well in my experience, it's nearly impossible to get the dust boots seated once the other lip is stretched around the piston so dust boots go in the caliper first then use compressed air to pop them around the pistons. And once the pistons are in they push the lip of the dust boot out into the groove in the caliper so it can't come out (or go in if its not already).
 
***MODERATOR NOTE***

Decided to crate a new thread for other owners to reference this issue in the future.

When using compressed air to "blow" the boot onto the piston, how do you prevent it from blowing out of the lip inside the caliper? What is the procedure? I assume you must do this before inserting the piston into the square seal?
 
***MODERATOR NOTE***

Decided to crate a new thread for other owners to reference this issue in the future.

When using compressed air to "blow" the boot onto the piston, how do you prevent it from blowing out of the lip inside the caliper? What is the procedure? I assume you must do this before inserting the piston into the square seal?

Insert square seal, then bellows \ boot. Position both pistons so they are touching the top of the boot using a timber packer above the pistons*. Then blow the compressed air through the bleed hole - don't give it full 'beans' if you have a super powerful compressor. Boots will not blow off, they will 'pop' around the pistons perfectly.
I wonder if the tyre compressor from the OEM tool kit may be powerful enough for this...never tried.

* I can't remember exactly but I'm pretty sure a 1/2" thick timber packer does the job. Was about 5 years ago when I last did mine.
 
Insert square seal, then bellows \ boot. Position both pistons so they are touching the top of the boot using a timber packer above the pistons*. Then blow the compressed air through the bleed hole - don't give it full 'beans' if you have a super powerful compressor. Boots will not blow off, they will 'pop' around the pistons perfectly.
I wonder if the tyre compressor from the OEM tool kit may be powerful enough for this...never tried.

* I can't remember exactly but I'm pretty sure a 1/2" thick timber packer does the job. Was about 5 years ago when I last did mine.

Keep your fingers clear of the piston just in case whenever using compressed air.

I have shop air and a rubber nozzle for my air gun. I always put a piece of scrap wood between the piston and caliper. I assume that is what a "timber packer" is in Her Majesty's English, but over here in the Colonies we call it scrap wood lol. ;) I'll give it a try with the rear calipers.
 
Your boots would've shot out using air before since they weren't inserted fully, once you jam the inner lip inside the caliper bore (Kaz's green arrow) they will never pop out, just fart around the piston until it pops over. It's actually a bit of a pain to stuff the seal in properly, you have to work around the inner circumference a few times to make sure there's no lip sticking out. It's impossible to put the boot in after the pistons.
 
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